Goodyear Marathon Tires

[SteveH]

Originally Posted by 2airishuman

a trailer spec'd with Cz (inflated to 50 psi) is NOT improved by going to Ez run at 50 psi.

the same is true for the majority of modern units with oem Dz run at 65 psi.

the notion of Ez somehow being better or an UPgrade is baseless in almost all trailer situations.

Ez do not have more ply or more layers of rubber/belts.

cheers
2air'

I believe these statements are 100% correct, and tire retailers have told me the exact same thing.

It is my opinion too many Airstreamers go to E rated tires believing them to be an upgrade, when if fact they are not if the extra weight capacity is not needed.

[dznf0g]

Primary shock absorbers on any vehicle or trailer are the tires. Secondary shock absorbers are hydraulic shocks. Springs/torsion rubber are not "shock absorbers" per se, but rather are there to suspend loads and allow controlled "movement" of components (and thus extend vehicle component operating life) and provide load "comfort". It could be argued that springs do absorb some shock, and that's true, but by definition they are not classified as "absorbers". Just watch those vehicles with worn shocks and struts going down the road. Road shock isn't being absorbed, it is being eventually dissipated through cyclical spring harmonics. That is "brakes and suspension 101", the very first automotive class I took, low those many years ago.
Yes, LREs have no more physical plys nor are "stiffer", but the belts/strands may be thicker/larger in diameter and/or may be of different material. This MAY allow more tearing strength (ie. tread separation, pothole bruising resistance, etc.) I have heard no one say that the rubber is any different in composition, so I don't believe they would have any greater resistance to heat delamination nor UV resistance, etc.

Given all that, I am struggling to believe that LREs run at 65 PSI are going to run at any significantly different temp, contact patch area or sidewall profile given the same loads and environmental inputs, than LRDs. Time will tell. That's why I'm dragging up this conversation...AGAIN. I think we should gather some accurate DATA, not "war stories".

It is my belief that be it LRD or LRE, since the sidewall stiffness and tread cord stiffness differential is negligible, the only variable is air pressure. Air is the ONLY component of the suspension holding the vehicle off the road. (OK, don't get nit picky here...tire has small influence) Basically, the tire's only purpose is to contain the air, protect the air from escaping due to road shock/hazard and provide firm contact consistent with the pavement. Air does the work of "lifting" and absorbing shock.

I THEORIZE (at this point) that really the only advantage to moving to LREs are (all other environmental/load inputs being equal, and not introducing brand quality into the mix):

1) perhaps a greater resistance to tread separation due to road shock and bruising
2) perhaps a greater amount of time, once a eminent tire failure is indicated by TPMS, to get off the road before total separation/destruction. (because of stronger belt material)

I don't consider the swap to be an upgrade or "mod", but rather, and only perhaps, a greater margin of protection and security against SOME of the hazards of pavement pounding.

My only concern is heat and the effect of running LREs at 65PSI instead of 80 PSI. That's where I need to see data. And I'm willing to give it a go and see what's up.

[2airishuman]

the primary/only documented feature of Ez is extra load rating when properly inflated.

none of the manufacturers claim more protection from belt/tread issues or road hazards or slower leak down times.

IF there were other benefits, no doubt the manufactures WOULD promote them in their adverts.
_________

having run years and 1000s of miles with D and and now E rated ST tires...

i have observed no difference in tire temps (d/65psi, e/70psi) during hot or warm weather, using infrared readings or tmps info.

with 3 axles my unit is well within the load rating for either and clearly the 34 does not need Ez.

i have yet to determine if they provide any greater durability/mileage.

cheers
2air'

[mwells4654]

Thanks 2air - you have stated what I have been trying to find out for the last year. Weather or not I need to go to an e rated tire. I think I will stay with Dz and now try to figure out which is the best tire for the $$$$$. I am gong to install a TPMS with the external sensors (metal valve stems). I think the "being able to change out the battery myself" instead of the internal sensor is my choice. Also, I can move them from TV to TV and TT to TT without going to the tire shop.

[dznf0g]

Thanks, 2 air,

You may well have answered the temp question. Although not with hard data...but I think you're at least as anal retentive as I am and I trust you observations
I too am well within the load limits of LRDs and only ASSUME that IF IN FACT, LREs have larger diameter strands and/or different materials in their belt and sidewall material to facilitate higher pressures and loads, that they would be more resistant to "stretching" and tearing when a failure or rupture starts to occur, especially at 65 psi, where the force on the failure point would be below what it would be at 80 PSI. (not sure I'm stating that point clearly)

I assume you're running 65 PSI on your LRDs? Marathons, I seem to recall from some other post?

Have you observed and can you share your observations relative to "normal" temp rises in varying conditions? (ie: differing regional climates, sunny side differentials, mountains and long downhill runs, brake heating effect etc?

[dznf0g]

Originally Posted by 2airishuman

the primary/only documented feature of Ez is extra load rating when properly inflated.

none of the manufacturers claim more protection from belt/tread issues or road hazards or slower leak down times.

IF there were other benefits, no doubt the manufactures WOULD promote them in their adverts.
_________

having run years and 1000s of miles with D and and now E rated ST tires...

i have observed no difference in tire temps (d/65psi, e/70psi) during hot or warm weather, using infrared readings or tmps info.

with 3 axles my unit is well within the load rating for either and clearly the 34 does not need Ez.

i have yet to determine if they provide any greater durability/mileage.

cheers
2air'

I have a feeling the reason we can't get detailed pressure clarifications from mfrs., especially relative to the industry/govt. pressure charts, as well as more clearly stated benefits and features of various tire models (LRD vs. LRE in this case) is spelled PRODUCT LIABILITY! That also affects their claims and adverts too, I believe. I also believe that is why mfrs. and dealers "default" to stating max. sidewall pressure are appropriate only. Keeps them out of trouble, because "we all lie or ignore" true loads, speeds,mechanical condition of the chassis, maintenance etc.....

THE TRUTH IS OUT THERE! (somewhere)

[jcanavera]

I would concur with 2air that running E's rather than D's or C's because they are stronger is not the real reasons why you should go to E's. I went to E's due to the weight of my heavy slide out and I felt that the reserve capacity I get (I think it was approx 300 lbs or so per tire @ 80 psi) was worthwhile. If it wasn't for that fact I'd still be using D's.

I did pick Maxxis over other brands due to the nylon cap that wraps the belts and is distinctive in Maxxis in that it minimizes belt squirm and its resultant heat generation. It's a concept used in high speed tires produced for Europe where speed limits are much higher.

So far we finished year 3 of service with no issues. My Canadian built Marathon's almost lasted four with one tire throwing a chunk of thread after 3 years and 10 months of service. End of next year will be a decision point for me as to either replace the Maxxis set for 2012 or go one last season and get 5 years out of them. We will see.

Jack

[SteveH]

Originally Posted by jcanavera

I did pick Maxxis over other brands due to the nylon cap that wraps the belts and is distinctive in Maxxis in that it minimizes belt squirm and its resultant heat generation. It's a concept used in high speed tires produced for Europe where speed limits are much higher.

Jack

Jack,

TowMaster ST tires also have this nylon belt. So far, I've had a set of each, TowMasters, and Maxxis, and wore them out without a failure.

[dznf0g]

Jack,

What is the load on your axles, loaded and ready to go? I thought a 30 slide was about 900 lbs heavier than a non-slide overall.

[Airslide]

Originally Posted by jcanavera

I would concur with 2air that running E's rather than D's or C's because they are stronger is not the real reasons why you should go to E's. I went to E's due to the weight of my heavy slide out and I felt that the reserve capacity I get (I think it was approx 300 lbs or so per tire @ 80 psi) was worthwhile. If it wasn't for that fact I'd still be using D's.

I did pick Maxxis over other brands due to the nylon cap that wraps the belts and is distinctive in Maxxis in that it minimizes belt squirm and its resultant heat generation. It's a concept used in high speed tires produced for Europe where speed limits are much higher.

So far we finished year 3 of service with no issues. My Canadian built Marathon's almost lasted four with one tire throwing a chunk of thread after 3 years and 10 months of service. End of next year will be a decision point for me as to either replace the Maxxis set for 2012 or go one last season and get 5 years out of them. We will see.

Jack

When I tell folks how much these S/O's weigh they are in total disbelief... They say...how can an Airstream weight that much? There is an ad showing a guy towing one with a bicycle..

[dznf0g]

Originally Posted by Airslide

When I tell folks how much these S/O's weigh they are in total disbelief... They say...how can an Airstream weight that much? There is an ad showing a guy towing one with a bicycle..

AND, just what load rating and belt material are those bicycle tires and at what pressure?

[Gene]

When I have compared some ST and LT tires and various load ranges one of things I look at is tread depth. So far as I can see tread ranges from 9/32 to 17 or 18/32. The Load Range E tires generally have more tread depth than C and D tires. This may provide a little more cushioning, but mainly it provides longer wear.

It also, in the case of LT mud and snow tires, means better performance in bad weather. Given that towing in snow is not enjoyable, using a snow tire adds some safety. You can't, so far as I know, get an ST tire with mud and snow tread.

These are 2 factors in choosing a tire.

Another factor is manufacturer. Some make better tires than others and some make some good tires and some bad ones. Checking ratings is helpful, but not always. Personal experience, while anecdotal, can be helpful—for more than 40 years I have almost always chosen on brand and had excellent performance and wear—better over the years and better than other brands I have bought or were OEM tires.

So, I knew what brand I wanted. I knew I wanted a mud and snow tire. I knew there are lots of reports—all anecdotal and a little (18,000 miles) experience—stating ST tires are bad tires, but little else to go on. There are also reports ST tires are fine. Some people who appear to understand the hazards of underpressure and otherwise treat their tires well, have had tread separation and blowouts as well as excessive wear.

I was probably moved along by my OEM wheels looking bad—clear coat coming off in splotches and the fact I was going to JC soon anyway.

I was also looking for a tire that would last 5 years with the amount of towing I do—I estimate 60,000 to 75,000 miles in that period of time. With 5 tires on nice wheels, rotated regularly, a tire rated at 60,000 miles means almost 75,000 miles of travel.

I also considered whether differences in sidewalls between ST and LT tires was an important factor. So far as I could tell, unless you are consistently backing at severe angles, it did not, and if it did, that was something I could control. If LT's perform better at highway speeds, that was a definite plus. That's another safety issue.

Some tires ride better than others. There are benefits to firmer or softer. Firmer could mean less sway, softer could mean less trailer trauma. People argue about this all the time and I cannot determine what is correct in the sense that differences in many cases may not be significant. It did seem to me a commercial truck tire was too firm. It was important to me that Michelin aims to make better riding tires—my experience is that, but it is based on a small sample. That experience includes Goodrich Load Range C OEM tires on my truck compared to the Michelin Load Range E tires I replaced them with—the difference in ride was significant. I don't know how the trailer rode on the Marathons or the Michelin tires I replaced them with, but I assume it's a better ride.

The Load Range E tires do not necessarily have more plies, but should be stronger. That seems like a good thing, but may be conventional wisdom.

While ST tires are not speed rated, LT's are. If the ST's were speed rated, many people assume it's 65 mph, or 75 if you add more air. This is based on assumptions and some statements on the Goodyear website that lead to more assumptions. But there is no use, so far as I know, of the government specs for speed rating. If the assumptions are true, a much higher speed rated tire, is a good thing.

Weighing all these factors, on almost all of them Michelin LTX was the winner. On fewer factors, it was a tie or I could not tell. The selection was a compromise because the evidence is never conclusive when it comes to trailer tires. The LTX A/T 2 was overkill—longer wear, more money, might have a lot of tread at 5 years.

This was a decision I agonized over, also thinking about the substantial amount of money involved.

I had no problems with the Marathons in 18,000 miles except they regularly lost air. Was it the valve stems? I replaced the original rubber ones with metal ones—but all 4 tires lost air before and after. The metal ones had seals on the outside and inside of the wheel (some don't), so it's unlikely the stems were the problem. I find it hard to believe it seeps through the rubber. Some claim nitrogen is a larger molecule than oxygen and oxygen leaks, nitrogen doesn't. But air has a lot of nitrogen in it and if you keep adding air, it would seem you have a larger and larger percentage of nitrogen, but the leaks stay the same. Was it the wheel? Maybe. Since I changed tires and wheels, and the wheels are a different brand, I have no basis to compare, but do know I don't lose air anymore.

I have had one leaking Michelin (trailer) and one flat (truck) this summer on the road to and in Alaska. The leak was caused by a screw (it sealed pretty well for a week and thousands of miles) and half a tire chain link caused a flat. I could blame the tires because a deeper tread does pick up things, primarily gravel. But when I examined the tires, I couldn't see the spaces between the tread blocks caused the problems—it's just fate and the roads you drive on.

I also know we both feel better. And a pretty worn Michelin tire performs just about as well as a new one—we've experienced that over and over.

Like dzn', I'd like more data and fewer war stories, but there doesn't seem to be much else. A lot of the "data" is largely customer reviews or Consumer Reports and I don't see the CR data to be that good. There are also manufacturer specifications which are data, but don't always tell me what I want to know.

As for heat, a thicker Load Range E tire may retain more heat and consequently may be built to resist it. I check pressure frequently and can't tell whether there is more pressure build up with the LT's than I had with the ST's. I don't know what causes a higher speed rating, but I imagine heat is part of it, and if so, a higher speed rating (LT's) may mean less heat. Pressure should be directly related to heat, probably or maybe, so a Load Range E tire, rated to 80 psi maximum, should build up less heat than a D tire with a 65 psi maximum. I don't know if my conclusions about heat are nonsense or a good guess.

There are a lot of variables and a lot of poor data, so tire selections leave plenty of room for opinions and lengthy, inconclusive threads.

Gene

[jcanavera]

Originally Posted by dznf0g

Jack,

What is the load on your axles, loaded and ready to go? I thought a 30 slide was about 900 lbs heavier than a non-slide overall.

Typical load without water is around 8,600 lbs. My axles are rated at 9,100 so when I load in 60 gallons of fresh water (like we do for the Moraine View rally), I'm pretty close to max axle load. The newer slide outs were load rated for just over 10,000 lbs. The center bath units like mine only have a half closet (single door). So I really don't have much more room to stash any more cargo. The side bath slide outs have the double door closet which gives you a lot more room for stuff.

Jack

[dznf0g]

Originally Posted by jcanavera

Typical load without water is around 8,600 lbs. My axles are rated at 9,100 so when I load in 60 gallons of fresh water (like we do for the Moraine View rally), I'm pretty close to max axle load. The newer slide outs were load rated for just over 10,000 lbs. The center bath units like mine only have a half closet (single door). So I really don't have much more room to stash any more cargo. The side bath slide outs have the double door closet which gives you a lot more room for stuff.

Jack

That's about what I thought, as I am at 7640 w/o slide. I don't run with much water in the tank tho. Just enough to water the dog, wash up, and use the rest room.

So why did you feel the E's would benefit you? D's take you to 10,160 lbs. at 65psi. E's give you another 1200 lbs. at 80 PSI. Are you running at 80 PSI or 65 PSI with your E's. Sorry, but your prior post confuses me.

[jcanavera]

Originally Posted by CrawfordGene

When I have compared some ST and LT tires and various load ranges one of things I look at is tread depth. So far as I can see tread ranges from 9/32 to 17 or 18/32. The Load Range E tires generally have more tread depth than C and D tires. This may provide a little more cushioning, but mainly it provides longer wear.

It also, in the case of LT mud and snow tires, means better performance in bad weather. Given that towing in snow is not enjoyable, using a snow tire adds some safety. You can't, so far as I know, get an ST tire with mud and snow tread.

These are 2 factors in choosing a tire.

Another factor is manufacturer. Some make better tires than others and some make some good tires and some bad ones. Checking ratings is helpful, but not always. Personal experience, while anecdotal, can be helpful—for more than 40 years I have almost always chosen on brand and had excellent performance and wear—better over the years and better than other brands I have bought or were OEM tires.


Gene

While I'll never know the reason why my Marathon peeled off a chunk of tread, I know it wasn't due to a lack of maintenance to air pressure. I was always a fanatic regarding checking tires before I pulled out and I know those tires were 65 psi cold.

I do think one additional factor you have to be cognitive of is the speed at which you tow. The faster you tow the more the tire has to flex. That in itself is why you have to understand that there is a point in speed where the tire and wheel cannot dissipate heat quickly enough to prevent the belts from separating thus causing more heat and eventual tire failure. Throw in under inflation to the mix, and you have a recipe for early tire failure.

The question becomes how hot does the tire have to get to cause failure? Obviously high speed towing in very hot conditions is rough on the tire. At a tire safety seminar that I went to sponsored by RVSelf, they talked a lot about speed being a large contributor to tire failure. Once the belts start to squirm in the early stages of separation, you are on the road for an eventual failure. It's just a matter of time at that point.

I've often thought of getting each wheel off the ground prior to a tow and doing a test spin to see if I see any variation in the tire dimensions. That might give you a heads up in catching belt slip prior to the point of failure.

Jack

[2airishuman]

Originally Posted by mwells4654

... I think I will stay with Dz and now try to figure out which is the best tire for the $$$$$. I am gong to install a TPMS with the external sensors (metal valve stems). I think the "being able to change out the battery myself" instead of the internal sensor is my choice. Also, I can move them from TV to TV and TT to TT without going to the tire shop.

mwells'

i am not making any specific tire recommendation, we each must reach our own rollin' rubber nirvana...

but this thread (starting around post #20) may offer you some insight

http://www.airforums.com/forums/f438...f-c-64182.html

being able to use the external tpms on multiple vehicles is nice,

as is being able to monitor spare tires or anything else with a shrader valve stem.

Originally Posted by SteveH

,,,TowMaster ST tires also have this nylon belt...

the GYMs also have this reinforced nylon belt (for the last 4 years)

the maxxis have a nylon CAP that extends from bead to bead, not a belt.

the cap IS important on low profile high performance tires (z, w, or y rated) but i doubt it does much on a tall, ST tire.
_________

this thread is about ST tires primarily.

there is no difference in tread depth for ST tires ranging from C 2 E ratings (they are all 9-10/32nds)
_________

Originally Posted by dznf0g

...I assume you're running 65 PSI on your LRDs? Marathons, I seem to recall from some other post?

Have you observed and can you share your observations relative to "normal" temp rises in varying conditions? (ie: differing regional climates, sunny side differentials, mountains and long downhill runs, brake heating effect etc?

i did run 65 psi in the Dz, now using Ez they are cold inflated to 70 psi.

most so the info is here (~posts #90-110)

http://www.airforums.com/forums/f438...ons-27999.html

the temp data over a wide range of conditions has been posted in many threads...

basically (tire internal air temps/not rubber temps) ..

-sunny side runs 10-20 degrees higher, this includes while PARKED/cold or towing.

-middle axle tires run 2-3 degrees higher than 1st or 3rd axle

-with disc brakes there has been essentially NO difference in tire temps while rolling/braking...

the vented rotors dissipate heat better than drums.

-after PARKING tire temps climb ~5 degrees after prolonged braking.

-when air temps are 60-85 degrees the tires typically run at 75-95 degrees (~ambient +10-15)

-when air temps (and roadway temps) approach 95-100, the tires run 110-130 depending on shade.

all the trailer data is compared to the TRUCK tire data...

-the load range E, LT tires on the truck (inflated to 75psi) are typically 10-30 degrees HOTTER than the trailer tires...

(i am using the same brand pressure/temp sensors of both vehicles)

i have no idea what the critical temp is for any of these tires (air or rubber temps)

but the truck tires are almost always 20-30 degrees warmer than the trailer tires.

most of the temp observations are while towing at 65-75 mph.

i have stopped using the laser surface temp gizmo now.

cheers
2air'

[jcanavera]

Originally Posted by dznf0g

That's about what I thought, as I am at 7640 w/o slide. I don't run with much water in the tank tho. Just enough to water the dog, wash up, and use the rest room.

So why did you feel the E's would benefit you? D's take you to 10,160 lbs. at 65psi. E's give you another 1200 lbs. at 80 PSI. Are you running at 80 PSI or 65 PSI with your E's. Sorry, but your prior post confuses me.

I do run at 80 psi and I just wanted a larger threshold of margin. At full load I'm at 90% capacity with the D rated tires. With the E's I'm just over 80%. No real scientific theory at this point. I'm more of a believer attempting to give myself a 20% margin. Maybe its not defensible but there is a matter of peace of mind.....and when I get out on those trips where air temps are in the high 90's and I'm highly loaded, it gives me a confidence level that isn't there otherwise.

Jack

[dznf0g]

Thanks, 2Air, I'm going to print that info out and use it as comparison while "playing" with pressures and Ds vs. Es.

I have asked several tire industry "experts" what the critical tire temp is for danger of delamination, etc. No one seems to know, or will tell.

[dznf0g]

2air,
I read through the linked post. Couple of questions After all those miles:

1) Did you notice any issues with running Ds at 65 PSI (BTW what it your loaded axle weight)? Indications of rough ride?

2) Why did you decide on 70 PSI with Es, as opposed to 65, 75, or 80?

[Wingeezer]

Originally Posted by jcanavera

No real scientific theory at this point. I'm more of a believer attempting to give myself a 20% margin. Maybe its not defensible but there is a matter of peace of mind

Jack

That's the same line of thought that is making me think I will feel more comfortable with E rated tired on my Classic 30 - just the same as I am happier towing well within the max tow rating of my truck, I will feel better with a greater capacity margin on my tires.

Don't know for sure that the logic holds water, but it feels right!

Brian.